1. Field
The following description relates to a method of performing a multi-point cooperation in a wireless communication system, and more particularly, to a method of performing a multi-point cooperation that may cluster base stations to participate in a multi-point cooperation based on a delay occurring due to the multi-point cooperation.
2. Description of Related Art
Multi-point cooperation technology enables a plurality of base stations or transmission nodes to cooperate with a terminal located at a cell boundary or a terminal having a weak reception signal, and to simultaneously transmit signals to a corresponding or neighboring terminal to thereby enhance a data rate at the terminal. In response to the terminal located at the cell boundary performing the multi-point cooperation, a propagation delay characteristic of a signal transmitted from a cooperation base station may vary depending on a distance between the cooperation base station and a terminal, and a communication environment. Accordingly, where a plurality of base stations simultaneously transmits signals to a corresponding terminal, the signals may be received by the terminal at various different points in time. A phenomenon that a delay time of each signal varies due to multiple paths may be referred to as a delay spread.
In a conventional wireless mobile communication system, each symbol may include a guard interval based on the delay spread. The guard interval functions to prevent inter-symbol interference. Generally, to prevent inter-channel interference, a guard interval zone may copy a portion of an end of a transmission symbol and transmit the copied portion, which is referred to as a cyclic prefix (CP). A cyclic prefix length may be determined based on a delay spread value. The inter-symbol interference or the inter-channel interference may not occur where the cyclic prefix length is greater than the delay spread value.
In the case of the multi-point cooperation, a multi-point cooperation gain may increase according to an increase in a number of base stations participating in the multi-point cooperation. However, in this case, the delay spread may also increase and the cyclic prefix length may also require an increase. As a result, the increase in the cyclic prefix length may cause an overhead, wasting radio resources.
Accordingly, in the case of the multi-point cooperation, a trade-off relationship may exist between a performance gain increasing according to an increasing in the number of cooperation base stations and the overhead occurring due to the increase in the cyclic prefix length.